Located at Loch Lochy in the Great Glen in the Scottish Highlands, exploratory works at Coire Glas got underway in December 2022 and are being conducted by Strabag, a world leader in mining and tunnelling projects.
Work so far has involved the creation of a tunnel approximately 4.5 metres wide, which is cut into the hillside, towards the proposed location of the underground powerhouse complex.
The purpose of the tunnel is to obtain information on the geological conditions to inform the detailed design for the main works.
Once complete, Coire Glas would be capable of delivering 30GWh of long duration storage. The scheme would take excess energy from the grid and use it to pump water 500 metres up hill from Loch Lochy to a vast upper reservoir equivalent to nearly 11,000 Olympic-sized swimming pools where it would be stored before being released to power the grid at a time when demand is high and/or other variable generation is low.
Pumped storage schemes involve two bodies of water at different heights. During periods of low demand and/or surplus generation, electricity is used to pump water from the lower loch to the upper reservoir, storing energy. The energy is released by using the water to generate hydro-electricity at a time when demand is high and/or other variable generation is low.
Coire Glas was selected as it has a large lower reservoir (Loch Lochy) and a significant elevation of more than 500m between the lower and the new upper reservoir site over a relatively short distance.
Of the project’s estimated cost of over £1.5 Billion, more than 70% is in the civil engineering structures.
